#include <string>
namespace constants{
	extern const std::string& ebook();
	extern const std::string& website();
	extern const std::string& name();
	extern const std::string& url();
	extern const std::string& file_name();
	extern const std::string& author();
	extern const std::string& view_date();
	extern const std::string& data_path();
	extern const std::string& subject();
	extern const std::string& sender();
	extern const std::string& receiver();
	extern const std::string& send_date();
	extern const std::string& log_date();
}
